docs: def tally_role_columns(self):
          """
          Sum up all of the stat columns.
          """
          totals = self.report["totals"]
          roles = self.report["roles"]
  
          totals["dependencies"] = sum(roles[item]
                                       ["total_dependencies"] for item in roles)
          totals["defaults"] = sum(roles[item]
                                   ["total_defaults"] for item in roles)
          totals["facts"] = sum(roles[item]["total_facts"] for item in roles)
          totals["files"] = sum(roles[item]["total_files"] for item in roles)
          totals["lines"] = sum(roles[item]["total_lines"] for item in roles)